The objectives of this project are to identify the etiology and the pathogenetic mechanisms of antigen-antibody reactions inducing inflammatory injury in the native kidneys or in the renal allografts of patients with glomerulo- or interstitial-nephritides. These studyes will be performed using serological techniques, light-, electron-, immunofluorescence- and immunoelectron-microscopy. Inflammatory lesions induced in extra-renal organs by antibodies or by antigen-antibody complexes will also be investigated by using the same techniques. Immunologically mediated renal and extra-renal diseases will be experimentally induced in animals and comparative studies will be performed.